Apparatus for weight coating pipe segments

ABSTRACT

An apparatus for molding a cementitious weight coating upon the exterior surface of pipe segments of the type to be laid upon the bed of a body of water. The mold includes a generally rectangular frame and a plurality of longitudinally extending arcuate form means which are designed to extend approximately the length of the frame base. A plurality of base support members are positioned at longitudinally spaced intervals along the frame in a posture generally transverse and upwardly extending with respect thereto for supporting a first portion of said plurality or arcuate form means longitudinally with respect to the frame. A first and second plurality of arcuate arm support members are pivotably connected to the free ends of the base support members in a position beneath a plane extending through the center line of the mold. The arcuate arms serve to support a second and third portion of said plurality of arcuate form means longitudinally with respect to the frame. Connecting means are provided between the free ends of the first and second plurality of arcuate arm support means for rigidly securing the support arms during a molding operation.

United States Patent 1 Rochelle et a].

[451 Mar. 25, 1975 APPARATUS FOR WEIGHT COATING PIPE SEGMENTS [75] Inventors: William R. Rochelle; Leroy N.

Larenzo; Eberhard V. Ranft, all of Houston, Tex.

[73] Assignee: Brown & Root, Inc., Houston, Tex.

[22] Filed: July 11, 1973 [21] Appl. No: 378,041

Primary Examiner-Roy Lake Assistant Examiner-DeWalden W. Jones Attorney, Agent, or Firm Burns, Doane, Sweclger dc Mathis [57] ABSTRACT An apparatus for molding a cementitious weight coating upon the exterior surface of pipe segments of the type to be laid upon the bed of a body of water. The

mold includes a generally rectangular frame and a plurality of longitudinally extending arcuate form means which are designed to extend approximately the length of the frame base. A plurality of base support members are positioned at longitudinally spaced intervals along the frame in a posture generally transverse and upwardly extending with respect thereto for supporting a first portion of said plurality or arcuate form means longitudinally with respect to the frame. A first and second plurality of arcuate arm support members are pivotably connected to the free ends of the'base support members in a position beneath a plane extending through the center line of the mold. The arcuate arms serve to support a second and third portion of said plurality of arcuate form means longitudinally with respect to the frame. Connecting means are provided between the free ends of the first and second plurality of arcuate arm support means for rigidly securing the support arms during a molding operation.

13 Claims, 9 Drawing Figures I z ATENTEUHAR25I975 SHEET 1 0F 4 fol PATENTED 5 5 snwsnm a QC APPARATUS FOR WEIGHT COATING PIPE SEGMENTS RELATED PATENT APPLICATION BACKGROUND OF THE INVENTION This invention relates to a method and apparatus for forming a weight coating upon the exterior surface of pipe segments. More specifically, the invention relates to a method and apparatus for molding a cementitious weight coating upon the exterior surface of steel pipe segments of the type designed to be connected end to end into a pipeline to be laid upon the bed of a body of water.

With the discovery of sizable oil and natural gas deposits offshore and the subsequent successful drilling and production thereof, a problem arose in connection with the most economical means for transporting the crude petroleum and/or natural gas from a producing offshore site to a shore location or collection/transfer terminal.

Often the most economical means for transporting oil and gas between offshore locations has been to establish submerged pipelines extending between the producing and collecting stations. In this connection United States Hauber et al. U.S. Pat. No. 3,280,571; Lawrence U.S. Pat. Nos. 3,390,532; 3,472,034; and 3,487,648; Rochelle et al. reissue U.S. Pat. No. Re. 27,420; Smith U.S. Pat. No. 3,566,609; Lochridge U.S. Pat. No. 3,606,759; Nolan U.S. Pat. No. 3,645,105 and Jones et al. U.S. Pat. No. 3,668,878, all assigned to the assignee of the subject invention, disclose highly effective methods and apparatus for laying a pipeline upon the bed of a body of water.

Although, as previously noted, the pipelines are fabricated from steel conduits, they typically displace more water than the weight of the pipe and the oil and- /or natural gas to'be carried by the line. As a consequence, offshore oil pipelines have a tendency to float within the body of water.

In order to eliminate this buoyant tendency, it has been the most common practice to coat the exterior of the pipe segments comprising the pipeline with a heavy cementitious weight coating of a thickness suitable to raise the specific gravity of the pipeline to a predetermined degree such as, for example, 1, 3 or more.

Various techniques have bee atleast theorized for applying a weightcojating tofieexterior surface of pipe segments.

In at least one instance, a specific composition was developed of the type which could be extruded onto the exterior'surface of pipe segments. The most desirable and commonly utilized cementitious composition for weight coating however, is not readily extrudable and therefore such equipment has met with a limited degree of commercial application.

Further, in many instances, it is desirable to vary the radical depth of the weight coating based upon variant specific gravity requirements of the pipeline. More particularly stated, in shallow water where storm waves may affect a line, it is desirable to specify high specific gravity per linear foot in order to minimize the possibility of pipeline shifting. On the other hand, in deeper water where the pipeline is less likely to be affected by storm conditions, and in order to minimize the amount of weight coating utilized, a lower specific gravity is desirable.

Therefore, notwithstanding the fact that the same diameter steel conduit may be utilized, it may be desirable to change the depth of the weight coating on a single job. Moreover, it may be desirable to change the diameter of the steel conduits utilized. Such a change will almost invariably dictate an alteration in the outside diameter of the weight coating utilized. Most extruding equipment is not designed to be readily adjusted and therefore is typically unsuited to the needs of the industry.

As a consequence of the foregoing varying requirements and the inability of a preferred composition of cementitious material to be extruded, it has been stan dard practice in the industry to spray coat cementitious material by hand upon the exterior surface of the pipe segments. By this technique varying diameters of pipe are accommodated as well as readily permitting varying depths of the weight coating to be applied.

Notwithstanding, however, the extensive commercial utilization of spray coating techniques, room for significant improvement remains. In this connection spray coating techniques frequently produce weight coatings which are not uniform in desired coating depth. Moreover, out of round difficulties always exist. Further, the surface finish of spray coatings tends to be rough and abrasive for handling equipment during a laying operation.

Accordingly, it would be highly desirable to provide a method and apparatus for rapidly applying a weight coating of cementitious material to the exterior of steel pipe segments which will provide a high degree of uniformity in coating depth and concentricity and further provide a high quality relatively smooth exterior surface finish. Moreover, it would be highly desirable to provide a method and apparatus for assuring the accuracy of depth measurement of the weight coating applied and thus precisely control the specific gravity per linear foot of the final weight coated product. Still further, it would be desirable to provide a method and apparatus for applying a weight coating material which could be adjusted to accommodate various diameter pipe segments as well as various depths of weight coating material.

In addition to the foregoing it would be highly desirable to provide the capability of casing or depositing a variety of materials within the coating which are not readily adaptable to deposit by the previously known impact or spraying techniques. Examples of such materials include large and/or round aggregate, nylon, polyester, polypropylene fibers, etc.

OBJECTS AND SUMMARY OF THE INVENTION Objects It is therefore a general object of the invention to provide a method and apparatus for applying a weight coating to the exterior surface of pipe segments which will obviate or minimize problems of the type previously described.

It is a particular object of the invention to provide a novel method and apparatus for mechanically applying a cementitious weight coating composition to the exterior surface of pipe segments.

ltis another object of the invention to provide a novel method and apparatus for applying a weight coating to the exterior surface of pipe segments which will provide a high quality resultant product of uniform thickness and thus accurately determinable specific gravity per linear foot of the resultant weight coated pipe segments.

It is yet another object of the invention to provide a novel method and apparatus for applying a weight coating composition to the exterior surface of pipe seg ments wherein the exterior surface of the weight coating material is notably smooth and highly accurate in concentricity about the pipe segments.

It is still another object of the invention to provide a novel method and apparatus for molding a cementitious weight coating to the exterior surface of steel pipe segments which will accommodate pipe of various diameters.

It is yet still another object of the invention to provide a novel method and apparatus for molding a cementitious weight coating composition upon the exterior surface of steel pipe segments wherein the depth of the weight coating may be varied from segment to segment notwithstanding the fact that the diameter of the steel pipe may remain constant.

It is a further object of the invention to provide a novel method and apparatus for molding a cementitious weight coating to the exterior surface of steel pipe segments wherein the amount of capital for the molding equipment may be minimized while providing a capability for accommodating various diameters of steel pipe segments to be weight coatedand varying depths of weight coating composition from one pipe segment to another.

It is yet a further object of the invention to provide a novel method and apparatus for molding a cementitious weight coating upon the exterior surface of pipe segments which is operable to facilitate removal of a pipe segment from the mold once the weight coating composition has solidified.

It is still a further. object of the invention to provide a novel method and apparatus for molding a cementitious weight coating material upon the exterior surface of steel pipe segments which is highly rugged in design and reliable in operation to accommodate large diameter heavy steel pipe segments while accurately maintaining the concentricity of the mold and the enclosed pipe segment while simultaneously providing a capability of manipulating the weighty mold apparatus during a molding operation.

It is still a further object of the invention to provide a novel method and apparatus for molding a weight coating upon the exterior surface of pipe segments wherein a variety of materials may be deposited in the coating.

BRIEF SUMMARY A method and apparatus suitable to accomplish at least some of the foregoing objects comprises a mold assembly having a generally rectangular frame anda plurality of longitudinally extending arcuate forming shoes connected thereto. A plurality of base support members are connected at longitudinally spaced intervals along the frame in a posture transverse and upwardly extending with respect thereto for supporting a first portion of the plurality of arcuate form shoes. A first and second plurality of arcuate arm support members are pivotally connected at one of the ends thereof to free ends of the base support members and serve to carry a second and third portion of said plurality of arcuate'forming shoes. Pillow block stands are provided at the ends of the mold for supporting a pipe segment to be weight coated concentrically within the interior of the plurality of longitudinally extending arcuate mold shoes. In order to open and close the mold, the first and second plurality of arcuate arm support members are pivotally connected to the plurality of base support members in a position below a plane extending through the axis of the mold. Thus, when the mold is opened at least more than of the surface of the weight coated pipe segment is exposed to facilitate removal of the weight coated segment from the mold.

A method designed to accomplish at least some of the foregoing objects includes the steps of opening a generally cylindrical mold by pivoting arcuate arm mold shoe carrying support members at pivotal locations horizontally below the center of the generally cylindrical mold and positioning a pipe segment to be weight coated into the mold supported coaxially therein upon pillow block stands. The mold is closed and the other ends of opposing arcuate arm mold carrying support members are connected to each other. A concentric seal is then applied at the ends of the mold and a cementitious weight coating composition is delivered into the cylindrical void between the interior of the mold forming shoes and the exterior of the steel pipe segment to be weight coated. The mold is maintained in a cylindrical configuration until the weight coating has solidified sufficient to be self-supporting. The mold is then opened by pivoting the arcuate arm mold shoe carrying support members at a position horizontally below the center line of the generally cylindrical mold to expose at least more than the upper 180 of the weight coated pipeline segment. The final step comprises removing the pipeline segment with the weight coating accurately molded thereupon.

THE DRAWINGS Other objects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments thereof taken in conjunction with the accompanying drawings wherein: 7

FIG. 1 is a plan view of a'manufacturing facility particularly suitable for utilizing molds of the present inve'ntion to apply a weight coating to the exterior sur as shown in FIG. 4 adjusted to mold a weight coating upon a pipe segment of a large diameter;

FIG. 6 is a detailed view of a radial adjustment assembly for longitudinally extending flexible mold shoes as depicted in FIGS. 4 and 5;

FIG. 7 is an adjustment assembly for longitudinally extending rigid mold shoes depicted at FIGS. 4 and 5;

FIG. 8 is a side elevational view of an alternate preferred embodiment of this invention comprising afixed rugged mold assembly and railway car underframe; and

FIG. 9 is a cross-sectional view taken along section line 9-9 in FIG. 8, and discloses a mold assembly of constant diameter mounted upon the mold car underframe.

DETAILED DESCRIPTlON General Operating Environment Referring now to the drawings and particularly to FIG. 1 thereof, there will be seen a plan view of a pipe segment weight coating plant 10 of the type which may advantageously utilize weight coating molds of the subject invention.

More specifically, cylindrical steel pipe segments of the type suitable to be connected end-to-end and laid upon the bed of a body of water are delivered to the plant 10 along a roadway 12. A pipe carrying vehicle such as a truck or the like (not shown) stops beneath an overhead crane assembly 14 which lifts the pipe from the truck and deposits it on an incoming pipe rack 16. The rack 16 is inclined from the unloading area 18 downwardly to a transfer area 20 so that the cylindrical pipeline segments will roll by gravity in the direction of arrow A.

The pipe to be weight coated is transferred from the rack 16 onto a skewed rollerconveyor assembly 22 and conveyed in the direction of arrow B through a shot blasting machine 24, and dust collector 26 to remove rust and scale. After being cleaned, the pipe segments are fed through an automatic priming collar 27 which applies a primer coat to the segments.

An outgoing skewed roller conveyor 28 transports the cleaned and primed pipe segments to a loading station 29 of astorage and primer drying rack 30. The rack 30 slopes downwardly from the loading station 29 to an unloading station 31. As gravity rolls the pipe in the direction of arrow C, the primer coating dries on the pipe segments.

The primed pipe segments are then deposited upon a skewed conveyor 32 and fed through an automatic coating and wrapping machine 34.

A pair of pipe buggies 36 support the pipe at the ends thereof following the coating operation and align the pipeline centrally between parallel cooling boards 38. The pipe segments are then rolled in the direction of arrow D on the cooling boards to cool and are finally rolled ontoa padded storage and transfer rack 40.

At the end of the transfer rack 40 the pipe segments are transferred onto a shuttle car 42, which is designed to position the coated and wrapped pipe segments in front of one of four padded pipe storage racks 44.

The pipe segments are then transferred on the storage racks to a reinforcing cage fabrication facility 46. Individual pipe segments are deposited upon one of four reinforcing wire cage installation tables 48.

Reinforcing wire is stored in large rolls in areas 50 at either end of the cage fabrication area. The rolls of wire are transferred to and mounted upon uncoiler assemblies 52. The uncoiled reinforcing wire passes over measuring tables 54. The sized wire reinforcing segments are then fed through straightening rollers 56 prior to being wrapped around the pipeline segments on the wire cage installation tables.

Once the wire cages have been installed, a top running single girder electric crane58 lifts the pipe segments to be weight coated and the attached reinforcing wire cage surrounding the segments and deposits the pipe into mold assemblies 60 comprising the subject matter of the instant invention.

The molds 60 are closed around the pipe segments to be weight coated and sealed by torus-shaped members (not shown) which are placed in the ends of the molds. The molds are then transferred, in the direction of arrow E, along a railway track 62 and longitudinally positioned upon a transversely movable transfer car 64.

Once a plurality of individual mold cars 60 have been assembled upon the transfer car 64 the car is translated in the direction of arrow F and into axial alignment with a plurality of parallel railway tracks 66. The individual mold cars are then pulled from the transfer car 64 onto the railway tracks 66 and proceed abreast therealong from right to left in the direction of arrow G.

The cementitious weight coating material to be molded upon the exterior surface of the pipe segments is mixed in a batch plant 68 and delivered by conventional cement conveying apparatus 70 into a longitudinally extending top opening in the individual molds 60.

The mold cars are elevated during filling so that the wheels are clear of the track by blader type air jacks. The entire mold cars are then vibrated during placing of the weight coating to assure maximum density and uniformity of the weight coating.

Once the molds have been filled they are moved to a preset station 71 and then into a curing kiln 72 where the cementitious weight coating material solidifies to a point of being self-supporting.

Following curing, a set of molds 60 containing weight coated pipe segments are translated abreast onto a transfer car 74 in a form stripping area 75.

In the form stripping area 75, the forms are opened by being pivoted beneath a horizontal plane extending through the axis of the cylindrical mold assembly to expose the weight coated pipe segments. An overhead crane assembly 76 serves to lift the individual weight coated pipe segments from the released molds and deposit the coated segments onto a transfer vehicle such as a truck (not shown) for delivery by way of a roadway 77 to a final curing and storage area.

The stripped molds are then translated in the direction of arrow H by the transfer car 74 to a cleaning area 80 where the forms are cleaned, treated to prevent weight coating from sticking to the forms and guided end-to-end back onto railway 62 to receive another pipe segment to be weight coated.

Adjustable Mold Assembly A mold assembly 60 comprising a preferred embodiment of the subject invention is depicted in FIGS. 2 through 7.

The mold assembly includes a generally rectangular frame including longitudinally extending beam side rails 92 and 94. The side rails are transversely con nected at a plurality of longitudinally spaced locations by crossing beam braces 96. The rigidity of the frame structure 90 is further enhanced by a plurality of cross bracings 98 and 100.

A plurality of railway trucks 102 underlie and rigidly support the frame 90 upon railway rails 104. More particularly, each railway 102 is provided with an axle 106 which is journaled through framing members 108 mounted beneath the frame assembly 90. Flanged wheels 110 are then journaled at each end of the axle 106 and ride directly upon rails 104.

The foregoing described ruggedized frame 90 and plurality of railway trucks 102 serve to rigidly, yet translatably, support a weight coating mold form to be discussed in detail herein presently. The frame design provides a rigid support for large, heavy steel pipe segments and the mold form to ensure uniform weight coating thickness and concentricity longitudinally throughout the pipe segment.

The side rails 92 and 94 serve to support in conjunction with transverse members 96 a plurality of base support members 112 at regular longitudinally spaced intervals along the extent of the frame 90.

As best illustrated in FIG. 4, the plurality of base support members 112 each comprise a first arcuate column 114 and a second arcuate column 116. Each of the columns is generally hollow and rectangular in cross section and is connected rigidly to the crossing braces 96 of the base assembly 90 by the provision of gusset plates 118 and 120.

First and second arcuate arms 122 and 124 are pivotally mounted as at 126 and 128 to the first and second arcuate columns 114 and 116 respectively. The arcuate arms like the arcuate columns are generally hollow and rectangular in cross section. The arcuate arms form in combination with the arcuate columns, in a closed posture, a generally cylindrical supporting framework such as depicted in solid lines in FIG. 4. When desired, the

arcuate arms 122 and 124 may be pivoted about the pivots 126 and 128, outwardly to open up the generally cylindrical supporting framework to permit the insertion and removal of pipe segments 130 as will be discussed more fully hereinafter.

A plurality of flexible forming shoes 140 longitudi nally extend approximately the length of the frame 90, note FIG. 2, and are peripherally positioned within the interior of the arcuate columns and arms. Each of the flexible forming shoes 140 is supported by a spoke 142 extending radially at regular circumferential locations inwardly from the arcuate columns and arms. The pluspect-to the plurality of flexible forming shoes 140,

note FIG. 4. v

Each of the rigid forming shoes 150 is radially adjustably supported with respect to the arcuate columns and arms by columns 152 which are preferably circular in cross section and adjustably connect to the cylindrical supporting structure at locations 154.

The rigid forming shoes 150 are designed to overlie the edges 160 and 162 of adjacent flexible forming shoes 140 and thereby serve to backup and bias the flexible shoes 140 into an arcuate configuration circumferentially spaced about a tubular conduit 130 to be weight coated.

With reference now to FIGS. 4 and 6, .details of the radial adjusting assemblies for the flexible forming shoes 140 are illustrated. More particularly, and with reference to FIG. 6, the adjustment spokes 142 are provided with exterior threads 164. An inner plate 166 of the arcuate columns and arms are provided with receiving apertures 168 to support in free rotation axial bearing members 170.

The bearing members 170 are provided with circumferentially extending flanges 172 and 174 positioned upon opposite sides of the plate 166. F ixedly welded to the flange 172 is an internally threaded fastener 176. Thus, when fastener 176 is turned, the spoke 142 may be radially translated inwardly or outwardly with respect to the supporting plate 166.

In order to fixedly maintain an adjusted radial position of the spoke 142, a jam nut 178 is also threaded upon the spoke. Once radial adjustment of the column 142 has been achieved, the nut 178 is rotated into firm abutting relationship with respect to nut 176 and thus accidental rotation of the shaft 142 is prevented.

In an analogous manner, the individual columns 152 which support the rigid forming shoes 150 are radially adjustably mounted at a plurality of locations 154 to the arcuate columns and arms.

With specific reference to FIGS. 4 and 7, it will be seen that the columns 152 are each provided with a plurality of regularly spaced apertures 180. The columns 152 extend through tubular sleeves 182 which in turn are mounted through the arcuate columns and arms. A pair of locking pins 184 extend through apertures 186 in the arcuate columns and arms, through the sleeves 186 and the adjusting apertures-180 of the radially projecting columns 152.

Time adjustment between the forming shoes 150 and the arcuate supporting columns and arms may be achieved by screwing columns 152 either in or out of threaded end connectors 151 of the rigid forming shoes 150 prior-to insertion of locking pins 184.

FIGS. 4 and 5 depict the extremities of adjustability of the mold forming a preferred embodiment of the invention.

More particularly, with reference to FIG. 4, it will be v seen that the flexible shoes 140 abut at longitudinally extending adjacent edges 160 and 162 directly beneath the center line of the rigid shoes 150. The rigid shoes 150 in this position are not utilized in a molding capacity per se but rather serve to backup and bias the edges of the flexible shoes 1400 into a cylindrical configuration.

The maximum cylindrical diameter that may be formed by the adjustable mold is depicted in FIG. 5. In

this connection it will be noted that the rigid forming shoes 150 are designed with arcuate inner surfaces 190. These surfaces have a curvature compatible with an imaginary cylinder which represents the largest diam eter of the weight coating cylinder 192 that may be applied to the exterior surface of a tubular conduit.

In the expanded posture depicted in FIG. 5 the edge surfaces 160 and 162 of the flexible forming shoes still underlie and are arcuately shaped by the rigid backup shoes 150, however, the arcuate surfaces of the rigid shoes also serve in a direct molding capacity.

shoes could be drawn against the rigid shoes until the desired cylindrical inner mold surface is achieved.

The actual depth X" of the weight coating material will be preselected based upon the desired specific gravity per linear foot of the finished product or for other reasons such as protection from external damage to the pipeline. Therefore, while relatively thin weight coatings 192 have been applied to the pipe segments 130 and 194 as depicted in FIGS. 4 and 5, it will be appreciated that a relatively thick weight coating may also be applied to the exterior surface of a tubular conduit if desired.

In order to open and close the generally cylindrical mold assembly formed by the flexible and rigid shoes, the plurality of arcuate arms may be pivoted outward with respect to the tubular conduits and weight coating material, note the phantom lines in FIGS. 4 and 5. The pivot points 126 and 128 are designed to be beneath the horizontal plane 200 which extends through the axis of the conduit to be weight coated, so that upon opening of the plurality of arms I22 and 124, the mold forming shoes 140 and 150 will be drawn away from the previously formed weight coating material, in a circumferential extent greater than 180 about the upper half of the weight coated pipeline segment.

By the provision of this wide opening mold assembly, the weight coated conduit is easily removed without scarring or disturbing the weight coating material which may not be fully cured.

In order to maintain the mold in a closed condition during the molding operation, a connecting bar 202 is connected between the free ends of opposing arcuate framing arms 122 and 124. The connecting bar 202 is releasably attached to the arms by conventional threaded fasteners 204.

In order to support the tubular conduit 130 coaxially within themold surface formed by the flexible and rigid shoes 140 and 150 respectively a pair of pillow block stands 206 are mounted upon the ends of the frame structure 90 (note FIG. 2). In order to provide a degree of longitudinal adjustability so that the form coating device may accommodate pipeline segments 130, which may vary in axial length, at least one of the pillow block stands 206 is mounted within a longitudinally adjustable rail frame assembly 208. Thus, in the event a conduit 130 of an irregular short length is encountered, the pillow block stand 206 may be moved from right to left as viewed in FIGS. 2 and 3 so as to still provide end support for the short conduit.

Fixed Mold Assembly While the above discussed adjustable mold assembly, as depicted in FIGS. 2-7, constitutes a preferred embodiment of the invention, an alternate embodiment of the invention is disclosed in FIGS. 8 and 9, where enhanced rigidity of the mold assembly is desired.

The alternate embodiment of the preferred invention comprises a non-adjustable molding assembly which is mounted upon a rigid generally rectangular base or frame 210. As previously discussed in connection with the adjustable form assembly, the underframe is mounted upon a plurality of railway trucks 212 which are positioned at regular longitudinally spaced intervals along the rectangular underframe. The railway trucks are designed to ride upon rails 214 and thus provide a sturdy support assembly for the weighty molding apparatus.

The mold per se comprises a plurality of longitudinally extending arcuate forming shoes 216, 218, and 220. The plurality of longitudinally extending arcuate form surfaces are supported at discrete longitudinally spaced intervals by a plurality of base support members 222 which are fixedly connected to the generally rectangular frame 210 by the provision of a plurality of gusset plates 224.

A first plurality of arcuate arm support means 226 are pivotally connected as at 228 to the base support means at regular longitudinally spaced intervals long the longitudinal extent of the underframe 210.

A second plurality of arcuate arm support means 230 are connected to the plurality of base support members 222 at pivot locations 232 along the longitudinal extent of the frame 210 and generally oppose the first plurality of arcuate arms 226.

The first and second plurality of arcuate arms are comprised of tee beams wherein the web portion varies in depth. More particularly the depth of the web is greatest at the mid span of the arm and tapers toward the free ends. This variation in depth provides required bending strength in the center section while minimizing the amount of reinforcing material utilized.

The first plurality of arcuate arms 226, the second plurality of arcuate arms 230 and the plurality of base means 222 are fixedly welded to and thus serve to sup port the plurality of longitudinally extending arcuate forming shoes 216, 218, and 220, respectively. A plurality of longitudinally extending backup plates 234 extend between the first and second plurality of arcuate arms and the respective arcuate form surfaces 216 and 218 along the longitudinal extent thereof.

As previously discussed, the first and second plurality of arcuate arms are pivotally connected to the base as at 228 and 232. This pivotal connection is below the horizontal plane 236 which extends through the axis of the mold assembly. Thus, when the plurality of arcuate arms 226 and 230, note the phantom representation in FIG. 9, are pivoted away from each other, the pipeline segment 238 which is provided with a molded weight coating 240 is exposed over an upper surface area greater than By the provision of this wide open mold assembly the pipe may be readily removed from the mold without damaging the partially cured weight coating material 240.

In order to maintain the forming surfaces 216 and 218 in a generally cylindrical posture, a plurality of coupling handles 242 are connected between the free ends 246 and 248 of the arcuate arms 226 and 230 re spectively.

In order to support the pipeline 238 to be weight coated concentrically within the generally cylindrical mold assembly, pillow blocks 250 are mounted at the ends of the underframe 210 and are vertically dimensioned to provide the desired coaxial relationship be tween the pipeline 238 and the interior surface of the cylindrical mold assembly.

Operation When the adjustable mold assembly is utilized, the plurality of flexible and rigid forming shoes will first be radially adjusted to a desired circumference by positioning the longitudinal center line of the flexible mold forming shoes upon the outer periphery of an imaginary cylinder having the desired circumference.

The rigid backup shoes are theninwardly adjusted to flex the edges of the flexible shoes inwardly into registry with the desired circumference.

Alternatively the rigid shoes could be set first at the desired circumference and the center line of the flexible shoes could then be drawn into registry with the desired imaginary cylinder.

Once adjustment is complete the connecting assemblies are locked and the mold is ready to receive pipe segments to be weight coated.

In this connection the mold is opened by pivoting the arcuate arm mold shoe carrying support members at the pivotal locations beneath the center line of the cylindrical mold. The pipe segments to be weight coated are'then lowered into the mold and supported at the ends thereof upon the pillow blocks exteriorly positioned at the ends of the rigid underframe.

The mold assembly is then closed and the upper ends of the arcuate arm support members are fixedly interconnected to maintain the cylindrical integrity of the mold during the forming operation. A longitudinal opening remains which runs along the top surface of the mold assembly to receive a weight coating'composition.

Once the mold is assembled about the pipe segment, the concentric void between the outer surface of the pipe segment and the inner surface of the mold assembly is filled with a fluid composition of weight coating material. The mold is then maintained in the previously set cylindrical configuration until the weight coating composition has at least solidified to a point of being self-supporting.

Once the weight coating composition is selfsupporting the cylindrical mold is opened by pivoting the arcuate arm support members at positions horizontally below the center line of the generally cylindrical mold to expose at least more than-the upper 180 surface ofthe green partially cured weight coating composition. The pipe segment and the green weight coating may then be removed from the mold assembly without scarring or tearing voids into the weight coating surface.

While the foregoing molding assembly has been-discussed with respect to molding a cementitious weight coating composition upon pipe segments, the subject method. and apparatus would also be highly useful with other compositions where the attributes and advantages of a molding operation are deemed necessary or desirable.

SUMMARY OF THE MAJOR ADVANTAGES OF THE INVENTION It will be appreciated that the foregoing specifically described mold assemblies which are mounted upon a secure and rigid railway underframe provide an accurate means for forming a weight coating of cementitious material upon the exterior surface of a pipeline segment.

The weight coating that is provided by the foregoing specifically describedmold assemblies may be characterized by the notable high quality, regular, smooth exterior surface which is highly accurate in concentricity about the steel pipeline segment throughout the longitudinal extent thereof. Because of the depth accuracy obtainable by utilizing the mold assemblies, the specific gravity per linear foot of the resultant weight coated pipeline may be finely designed.

.and weight coated material may be readily removed from the forming assembly without scarring or stripping away any of the weightcoating material.

Still further it will be realized that the subject unitized mold assembly and underframe structure is highly rugged in design and will be reliable in operation. Moreover, in the preferred embodiment, the subject mold assembly will be suitable to accommodate pipelines of various diameters or weight coatings of various thicknesses upon pipe segments of constant diameter.

A still further advantage of the preferred embodiment of the invention is the provision of an apparatus for molding a cementitious weight coating material to the exterior surface of steel pipe segments wherein the amount of capital for molding equipment may be minimized by providing a capability of accommodating various diameter steel pipe segments or various depths of weight coating material for constant diameter pipe segments.

While the invention has been described with reference to preferred embodiments, it will be appreciated by those skilled in the art that additions, deletions, modifications and substitutions, or other changes not specifically described may be made which will fall within the purview of the appended claims.

What is claimed is:

l. A mold for forming a weight coating upon the exterior surface of pipe segments comprising:

a generally rectangular frame;

a plurality of transversely mounted railway trucks positioned beneath said frame at longitudinally spaced regular intervals for translatably supporting said generally rectangular frame upon parallel railway rails;

a plurality of longitudinally extending arcuate formmeans extending approximately the length of said frame for forming a cylindrical weight coating upon the exterior surface of a pipe segment;

a plurality of base support means connected at longitudinally spaced intervals along said frame and generally transversely, upwardly extending with respect to said frame for supporting a first portion of said plurality of arcuate form means longitudinally with respect to said frame;

a first plurality of arcuate arm support means, one being pivotally connected at one end thereof to one end of each of said base support means, for supporting a second portion of said plurality of arcuate form means longitudinally with respect to said frame and being operable to support in pivotal movement said at least a second portion of said plurality of arcuate from means in registry with and away from an imaginary cylindrical surface formed by a circumferential continuation of the curvature of said first portion of said plurality of arcuate form means connected to said plurality of base support means;

a second plurality of arcuate arm support means, one being pivotally connected at one end thereof to the other end of each of said'base support means and opposing said first plurality of arcuate arm support means for supporting a third portion of said plurality of arcuate form means longitudinally with respect to said frame and being operable to support in pivotal movement said third portion of said plurality of arcuate form means in registry with and away from the imaginary cylindrical surface formed by a circumferential continuation of the curvature of said first portion of said plurality of arcuate form means connected to said plurality of base support means;

means connected between at least a plurality of the other ends of opposing ones of said first and second plurality of arcuate arm support means for selectively holding against separation said first and second plurality of opposing arcuate arm support means in a posturewhere the first, second and third portion of said plurality of arcuate form means abut to provide a substantially closed cylindrical form;

means for supporting a pipe segment to be weight coated concentrically within the interior of said cylindrical form means;

a a longitudinally extending opening in the top surface of said substantially closed cylindrical form means to prevent deposit of a weight coating composition within said cylindrical form and about the pipe segment position therein; and

said first'and second plurality of arcuate arm support means being each pivotally connected to a corresponding base support means in a posture horizontally below the central axis of the substantially closed cylindrical form, whereby parting of said first and second plurality of arcuate arm support means and said second and third portions of said plurality of arcuate form means carried thereby respectively will expose more than the upper 180 surface of the weight coated pipe segment for facilitating unobstructed removal of the weight coated pipe segment from the mold.

2. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 1 wherein said base support means each comprise:

an arcuate member symmetrically mounted transversely across said frame and having a curvature coincident with the curvature of said first portion of said plurality of arcuate form means, said first portion being directly mounted upon the arcuate members;

3. A mold for forming a weight coating upon the-exterior surface of pipesegments as defined in claim 2 wherein said first and second plurality of arcuate arm support means each comprise:

an arcuate tee beamhaving an arcuate flange and an arcuate variable depth web wherein the greatest depth of the web being at the midpoint of the extent thereof and tapering therefrom approximately equally to the ends of the web.

4. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 1 wherein said base support means each comprise:

a first generally upwardly projecting arcuate column on one side of said frame; and

a second generally upwardly projecting arcuate column opposing said first generally upwardly projecting column on the other side of said frame 5. A mold for forming a weight coating upon the exterior surface of piper segments as defined in claim 4 wherein said first and second plurality of arcuate arm support means each comprise:

arcuate tubular beams of generally constant sectional configuration.

6. A mold for forming a weightcoating upon the exterior surface of pipe segments as defined in claim 1 wherein said plurality of longitudinally extending arcuate form means comprise:

a plurality offlexible forming shoes connected to said plurality of base support means, said first plurality of arcuate arm support means, and said second plurality of arcuate arm support means by radially inwardly projecting spokes extending between respective ones of said plurality of flexible forming shoes and said plurality of base, first plurality of arcuate arm, and second plurality of arcuate arm support means; and

a plurality of rigid forming shoes connected to said plurality of base support means, said first plurality of arcuate arm support means, and said second plurality of arcuate arm support means by radially inwardly directed columns extending between re spective ones of said plurality of flexible forming shoes and said plurality of base, first plurality of arcuate arm, and second plurality of arcuate arm support means, and being alternately spaced with said plurality of flexible forming shoes and lying radially outwardly with respect to said plurality of flexible forming shoes to overlap and backup the edges of said flexible forming shoes.

7. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 6 wherein:

said plurality of rigid forming shoes are each fashioned with an arcuate inwardly projecting surface.

8. A mold for forming a weight coating upon the ex terior surface of pipe segments as defined in claim 7 wherein:

the curvature of each of the arcuate surfaces of said rigid forming shoes is approximately coincident with that of an imaginary cylindrical surface of the largest diameter weight coating cylinder capable of being molded to the exterior surface of a pipe segment by the mold.

9. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 6 wherein:

said radially inwardly directed spokes supporting said plurality of flexible forming shoes and said radially inwardly directed columns supporting said plurality of alternate rigid forming shoes being radially adjustable with respect to said plurality of base, first plurality of arcuarte arm and second plurality of arcuate arm support means.

10. An adjustable mold for forming a weight coating upon the exterior surface of pipe segments comprising:

a generally rectangular frame;

a plurality of opposing pairs of arcuate columns up- CI'OSS- wardly coextending at a plurality of spaced intervals along the longitudinal extent of said frame;

a plurality of arcuate arms, one arm being pivotally connected to the free end of each of said arcuate columns and serving in combination with said columns to form a generally circumferential support at a plurality of spaced intervals along the longitudinal extent of said frame;

a plurality of flexible forming shoes longitudinally extending approximately the length of said frame;

. a plurality of spokes radially and adjustably inwardly projecting from said circumferential supports and connected to said flexible forming shoes for adjustably supporting said shoes within said circumferential supports;

a plurality of rigid forming shoes longitudinally extending approximately the length of said frame and circumferentially alternately spaced and radially outwardly positioned with respect to said plurality of flexible forming shoes to overlap and backup the edges of said flexible forming shoes; and

a plurality of columns radially and adjustably inwardly projecting. from said circumferential supports and connected to said rigid forming shoes for adjustably supporting said rigid forming shoes within said circumferential supports;

whereby said rigid forming shoes are operable to backup and flex the longitudinal edges of said flexible forming shoes into an arcuate configuration coincident with the exterior surface of an imaginary cylindrical configuration desired of a molded weight coating to be applied upon a pipe segment.

11. An adjustable mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 10 and further comprising:

a plurality of transversely mounted railway trucks positioned beneath-said generally rectangular frame at longitudinally spaced intervals for translatably rigidly supporting said generally rectangular frame upon parallel railway rails throughout the longitudinal extent of the adjustable mold.

12. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 10 wherein:

said plurality of rigid forming shoes are each fashioned with an arcuate inwardly projecting surfaces.

13. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 12 wherein:

the curvature of each of the arcuate surfaces of said rigid forming shoes is approximately coincident with the curvature of an imaginary cylindrical surface of the largest diameter weight coating cylinder capable of being molded to the exterior surface of pipe segments within the mold. 

1. A mold for forming a weight coating upon the exterior surface of pipe segments comprising: a generally rectangular frame; a plurality of transversely mountEd railway trucks positioned beneath said frame at longitudinally spaced regular intervals for translatably supporting said generally rectangular frame upon parallel railway rails; a plurality of longitudinally extending arcuate form means extending approximately the length of said frame for forming a cylindrical weight coating upon the exterior surface of a pipe segment; a plurality of base support means connected at longitudinally spaced intervals along said frame and generally transversely, upwardly extending with respect to said frame for supporting a first portion of said plurality of arcuate form means longitudinally with respect to said frame; a first plurality of arcuate arm support means, one being pivotally connected at one end thereof to one end of each of said base support means, for supporting a second portion of said plurality of arcuate form means longitudinally with respect to said frame and being operable to support in pivotal movement said at least a second portion of said plurality of arcuate from means in registry with and away from an imaginary cylindrical surface formed by a circumferential continuation of the curvature of said first portion of said plurality of arcuate form means connected to said plurality of base support means; a second plurality of arcuate arm support means, one being pivotally connected at one end thereof to the other end of each of said base support means and opposing said first plurality of arcuate arm support means for supporting a third portion of said plurality of arcuate form means longitudinally with respect to said frame and being operable to support in pivotal movement said third portion of said plurality of arcuate form means in registry with and away from the imaginary cylindrical surface formed by a circumferential continuation of the curvature of said first portion of said plurality of arcuate form means connected to said plurality of base support means; means connected between at least a plurality of the other ends of opposing ones of said first and second plurality of arcuate arm support means for selectively holding against separation said first and second plurality of opposing arcuate arm support means in a posture where the first, second and third portion of said plurality of arcuate form means abut to provide a substantially closed cylindrical form; means for supporting a pipe segment to be weight coated concentrically within the interior of said cylindrical form means; a longitudinally extending opening in the top surface of said substantially closed cylindrical form means to prevent deposit of a weight coating composition within said cylindrical form and about the pipe segment position therein; and said first and second plurality of arcuate arm support means being each pivotally connected to a corresponding base support means in a posture horizontally below the central axis of the substantially closed cylindrical form, whereby parting of said first and second plurality of arcuate arm support means and said second and third portions of said plurality of arcuate form means carried thereby respectively will expose more than the upper 180* surface of the weight coated pipe segment for facilitating unobstructed removal of the weight coated pipe segment from the mold.
 2. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 1 wherein said base support means each comprise: an arcuate member symmetrically mounted transversely across said frame and having a curvature coincident with the curvature of said first portion of said plurality of arcuate form means, said first portion being directly mounted upon the arcuate members.
 3. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 2 wherein said first and second plurality of arcuate arm support means each comprise: an arcuate tee beam having an arcuate flange and an arcuate variable depth web wherein the greatest depTh of the web being at the midpoint of the extent thereof and tapering therefrom approximately equally to the ends of the web.
 4. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 1 wherein said base support means each comprise: a first generally upwardly projecting arcuate column on one side of said frame; and a second generally upwardly projecting arcuate column opposing said first generally upwardly projecting column on the other side of said frame.
 5. A mold for forming a weight coating upon the exterior surface of piper segments as defined in claim 4 wherein said first and second plurality of arcuate arm support means each comprise: arcuate tubular beams of generally constant cross-sectional configuration.
 6. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 1 wherein said plurality of longitudinally extending arcuate form means comprise: a plurality of flexible forming shoes connected to said plurality of base support means, said first plurality of arcuate arm support means, and said second plurality of arcuate arm support means by radially inwardly projecting spokes extending between respective ones of said plurality of flexible forming shoes and said plurality of base, first plurality of arcuate arm, and second plurality of arcuate arm support means; and a plurality of rigid forming shoes connected to said plurality of base support means, said first plurality of arcuate arm support means, and said second plurality of arcuate arm support means by radially inwardly directed columns extending between respective ones of said plurality of flexible forming shoes and said plurality of base, first plurality of arcuate arm, and second plurality of arcuate arm support means, and being alternately spaced with said plurality of flexible forming shoes and lying radially outwardly with respect to said plurality of flexible forming shoes to overlap and backup the edges of said flexible forming shoes.
 7. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 6 wherein: said plurality of rigid forming shoes are each fashioned with an arcuate inwardly projecting surface.
 8. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 7 wherein: the curvature of each of the arcuate surfaces of said rigid forming shoes is approximately coincident with that of an imaginary cylindrical surface of the largest diameter weight coating cylinder capable of being molded to the exterior surface of a pipe segment by the mold.
 9. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 6 wherein: said radially inwardly directed spokes supporting said plurality of flexible forming shoes and said radially inwardly directed columns supporting said plurality of alternate rigid forming shoes being radially adjustable with respect to said plurality of base, first plurality of arcuarte arm and second plurality of arcuate arm support means.
 10. An adjustable mold for forming a weight coating upon the exterior surface of pipe segments comprising: a generally rectangular frame; a plurality of opposing pairs of arcuate columns upwardly coextending at a plurality of spaced intervals along the longitudinal extent of said frame; a plurality of arcuate arms, one arm being pivotally connected to the free end of each of said arcuate columns and serving in combination with said columns to form a generally circumferential support at a plurality of spaced intervals along the longitudinal extent of said frame; a plurality of flexible forming shoes longitudinally extending approximately the length of said frame; a plurality of spokes radially and adjustably inwardly projecting from said circumferential supports and connected to said flexible forming shoes for adjustably supporting said shoes within said circumferentiaL supports; a plurality of rigid forming shoes longitudinally extending approximately the length of said frame and circumferentially alternately spaced and radially outwardly positioned with respect to said plurality of flexible forming shoes to overlap and backup the edges of said flexible forming shoes; and a plurality of columns radially and adjustably inwardly projecting from said circumferential supports and connected to said rigid forming shoes for adjustably supporting said rigid forming shoes within said circumferential supports; whereby said rigid forming shoes are operable to backup and flex the longitudinal edges of said flexible forming shoes into an arcuate configuration coincident with the exterior surface of an imaginary cylindrical configuration desired of a molded weight coating to be applied upon a pipe segment.
 11. An adjustable mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 10 and further comprising: a plurality of transversely mounted railway trucks positioned beneath said generally rectangular frame at longitudinally spaced intervals for translatably rigidly supporting said generally rectangular frame upon parallel railway rails throughout the longitudinal extent of the adjustable mold.
 12. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 10 wherein: said plurality of rigid forming shoes are each fashioned with an arcuate inwardly projecting surfaces.
 13. A mold for forming a weight coating upon the exterior surface of pipe segments as defined in claim 12 wherein: the curvature of each of the arcuate surfaces of said rigid forming shoes is approximately coincident with the curvature of an imaginary cylindrical surface of the largest diameter weight coating cylinder capable of being molded to the exterior surface of pipe segments within the mold. 